Dr. Jun Wu collaborated with UCLA researchers on a study that examined prenatal exposure to ambient pesticides and adverse birth outcomes in agricultural regions of California. Pesticide exposures within 2 km of residential addresses at birth by pregnancy trimester for 17 individual pesticides and three chemical classes (organophosphates, pyrethroids, and carbamates) were estimated. The researchers found that first or second trimester exposure to individual pesticides (e.g., glyphosates, paraquat, imidacloprid) or exposure to 2 or more pesticides in the three chemical classes were associated with a small increase (3–7%) in risk for preterm birth and the associations were stronger for female offspring.